Northern lights take unusual trip down south

In this photo provided by Brian Emfinger, aurora borealis lights up the Ozark, Ark. sky on Monday, Oct. 24, 2011. Emfinger, a storm chaser, said this is only the second northern lights in a decade that he has seen this far south.
(AP Photo/realclearwx.com, Brian Emfinger)

A storm-chasing photographer captured the strange sky show in Arkansas Monday night. People in Kentucky and Georgia reported their sightings to local television stations. A special automated NASA camera that takes a picture of the sky every minute in Huntsville, Ala., captured 20 minutes of the vibrant red and green aurora borealis.

In Arkansas, Brian Emfinger called the view "extremely vivid, the most vivid I have ever seen. There was just 15 to 20 minutes where it really went crazy."

He called it "a much bigger deal" than a tornado" because he sees dozens of those every year. This is only the second northern lights in a decade that he has seen this far south.

"They are very rare events," said NASA scientist Bill Cooke, who found the aurora photos in the Alabama camera's archive and posted them on the Marshall Space Flight Center's blog. "We don't see them this far south that often."

Officials at the federal Space Weather Prediction Center in Boulder, Colo., said they were surprised at the southern reach. The center monitors solar storms, which trigger auroras.

Space weather forecast chief Bob Rutledge said given the size of the solar storm, the lights probably shouldn't have been visible south of Iowa. The storm was only considered "moderate" sized, he said.

He called the storm unusual, its effects reaching Earth eight hours faster than forecast. But that timing made it just about perfect for U.S. viewing, he said.

"The peak of the intensity happened when it was dark or becoming dark over the U.S., coupled with the clear skies. We did have significant aurora sightings," Rutledge said. "The timing was good on this."

In Huntsville, the aurora lasted from 8:25 p.m. to 8:45 p.m. CDT, Cooke said. In Arkansas, Emfinger went out shortly after sunset after getting a space weather alert. He saw auroras that lasted until after 11 p.m.

An aurora begins with a storm shooting a magnetic solar wind from the sun. The wind slams into Earth's magnetic field, compressing it. That excites electrons of oxygen and nitrogen. When those excited electrons calm down, they emit red and green colors, Rutledge said.

Often solar storms can cause damage satellites and power grids. This one didn't, Rutledge said.